/***************************************************************************
 *  CastFunctionSet.cs
 *
 *  Copyright (C) 2007 Novell, Inc.
 *  Written by Aaron Bockover <abockover@novell.com>
 ****************************************************************************/

/*  THIS FILE IS LICENSED UNDER THE MIT LICENSE AS OUTLINED IMMEDIATELY BELOW: 
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a
 *  copy of this software and associated documentation files (the "Software"),  
 *  to deal in the Software without restriction, including without limitation  
 *  the rights to use, copy, modify, merge, publish, distribute, sublicense,  
 *  and/or sell copies of the Software, and to permit persons to whom the  
 *  Software is furnished to do so, subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in 
 *  all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
 *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
 *  DEALINGS IN THE SOFTWARE.
 */

using System;

namespace SExpEngine
{
    public class CastFunctionSet : FunctionSet
    {
        [Function("cast-double")]
        public virtual TreeNode OnCastDouble(TreeNode [] args)
        {
            if(args.Length != 1) {
                throw new ArgumentException("cast must have only one argument");
            } 
            
            TreeNode arg = Evaluate(args[0]);

            if(arg is DoubleLiteral) {
                return arg;
            } else if(arg is IntLiteral) {
                return new DoubleLiteral((int)(arg as IntLiteral).Value);
            } else if(arg is StringLiteral) {
                return new DoubleLiteral(Convert.ToDouble((arg as StringLiteral).Value));
            } 
            
            throw new ArgumentException("can only cast double, int, or string literals");
        }
        
        [Function("cast-int")]
        public virtual TreeNode OnCastInt(TreeNode [] args)
        {
            DoubleLiteral result = (DoubleLiteral)OnCastDouble(args);
            return new IntLiteral((int)result.Value);
        }
        
        [Function("cast-bool")]
        public virtual TreeNode OnCastBool(TreeNode [] args)
        {
            DoubleLiteral result = (DoubleLiteral)OnCastDouble(args);
            return new BooleanLiteral((int)result.Value != 0);
        }
        
        [Function("cast-string")]
        public virtual TreeNode OnCastString(TreeNode [] args)
        {
            if(args.Length != 1) {
                throw new ArgumentException("cast must have only one argument");
            }
            
            TreeNode arg = Evaluate(args[0]);
            
            if(arg is DoubleLiteral) {
                return new StringLiteral(Convert.ToString((arg as DoubleLiteral).Value));
            } else if(arg is IntLiteral) {
                return new StringLiteral(Convert.ToString((arg as IntLiteral).Value));
            } else if(arg is StringLiteral) {
                return arg;
            }
            
            throw new ArgumentException("can only cast double, int, or string literals");
        }
    }
}
